This invention relates in general to improvements in internal combustion engines and, more specifically, to an improved cylinder head and piston arrangement with an improved valve and spark plug layout for use in those engines.
A great many different intake and exhaust valve arrangements have been developed over the years for use in internal combustion engines, in particular for use in automobiles and motorcycles. Many such engines use one intake valve and one exhaust valve at each cylinder with a single spark plug. The combustion chambers are generally formed by a curved, typically hemispherical, chamber in the head and a flat piston face. A great deal of effort has gone into optimizing the sizing and placement of the valves, the shape of the combustion chamber and the like. Since there is a great need for improvements in engine fuel efficiency while maintaining or improving performance, a wide variety of different valve and spark plug configurations and arrangements have been designed and tested.
Suzuki et al. describes in U.S. Pat. No. 4,742,804 a number of combustion chamber designs using one or more intake valves, one or more exhaust valves and plural spark plugs. While quite efficient, the spark plugs and valves are offset from the chamber center and from each other in a manner which provides less than optimum combustion and the arrangement is complex and expensive to manufacture.
A number of modern high performance automobile engines use two intake valves and two or more exhaust valves with one or more spark plugs, generally arranged around the chamber periphery. Typical of these systems is that disclosed by Akana in U.S. Pat. No. 3,411,490. Manufacture and operation of four valve, multiple spark plug engines is complex and expensive and requires complex computer control for efficient operation.
Complex cylinder head arrangements, with one intake valve and one exhaust valve in the main combustion chamber adjacent to the piston and an auxiliary chamber communicating with the main chamber and having an intake valve. One or more spark plugs are provided in the auxiliary chamber and/or the main chamber. As described by Weslake in U.S. Pat. No. 2,652,039 and Von Segern et al. in U.S. Pat. No. 3,443,552, combustion may be initiated in the auxiliary chamber and spread to the main chamber where additional fuel is introduced. Again, these are complex and cumbersome systems that appear to have been unsuccessful and never have been brought into production.
Thus, while a great number of different arrangements of intake and exhaust valves and spark plugs have been designed, using a variety of combustion chamber shapes, none have provided an optimum combination of structural simplicity, maximum fuel efficiency and highest performance. Thus, despite the very extensive research and development over many years in this field and crowded nature of the internal combustion engine fuel combustion chamber art, there remains a continuing need for improvements providing greater overall efficiency at lowest cost.
It is, therefore, an object of this invention is to provide an improved combustion chamber arrangement having increased operating efficiency. Another object is to provide such as system that provides both increased fuel efficiency and higher performance. A further object is to provide such a system with high thermal efficiency and low heat retention. Yet another object is to provide a system capable of operating at high compression ratios. A further object is to provide a system capable of operating with a wide variety of fuels. An additional object is to provide a system capable of easy and economical retro-fitting into existing engines.